Simpson et al. (2019) conducted a phase II, double-blind, and placebo-controlled trial in 185 adult patients; they observed a dose–response relationship between 40 mg of apremilast administered twice daily and a significant remission in moderate-to-severe AD, with gene array analysis displaying reduced levels of the Th17/Th22-associated biomarkers, including IL-19, IL-22, and S100A, in AD lesions. This evidence concerns the gene IL22 and Alzheimer disease.